Progestogen (breast/endometrial cancer)
Medroxyprogesterone is a progestogen hormone used in the palliative treatment of hormone-dependent cancers (breast, endometrium) and in other gynaecological indications. As a hormone, it interferes with the hormonal environment that feeds some tumours, helping to control the disease. It has moderate adverse effects and requires exclusion of pregnancy before starting.
Also known as: Medroxiprogesterona, Provera
Medroxyprogesterone + rifampicin: rifampicin (CYP3A4 inducer) may reduce the effect of medroxyprogesterone.
Medroxyprogesterone is metabolised mainly by hydroxylation via CYP3A4 ("Medroxyprogesterone acetate is metabolized in-vitro primarily by hydroxylation via the CYP3A4"), and the Prontuário documents "Rifampicin: reduction of effect". Rifampicin, a potent CYP3A4 inducer, accelerates progestogen metabolism and reduces its exposure, which may compromise hormonal control of breast or endometrial cancer. The consequence is possible loss of therapeutic efficacy during concomitant use. Monitor clinical response to hormonal therapy and consider a therapeutic alternative or adjustment when the combination is unavoidable (e.g., concomitant tuberculosis treatment). Level monitoring is not routine — the criterion is clinical.
Medroxyprogesterone + rifampicin: monitor hormonal response — rifampicin may reduce the effect (CYP3A4 induction).
Medroxyprogesterone is metabolised mainly by hydroxylation via CYP3A4 (FDA label: "Medroxyprogesterone acetate is metabolized in-vitro primarily by hydroxylation via the CYP3A4... Inducers and/or inhibitors of CYP3A4 may affect the metabolism of MPA"). Rifampicin, a potent inducer, accelerates metabolism and reduces exposure — the Prontuário documents: "Rifampicin: reduction of effect".
Periodic clinical assessment of response (oncological/hormonal control) during the combination.
Loss of disease control or recurrence of symptoms during concomitant rifampicin use.
Monitor clinical response to hormonal therapy; consider an alternative or adjustment if efficacy is lost during rifampicin combination.
DailyMed/FDA (NIH/NLM) — approved Medroxyprogesterone label (PROVERA): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a586be28-96af-4fed-a13f-9b94fd4c7405 ; approved Rifampicin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b389b1a3-672f-47e3-916c-4a9c044b211b ; Prontuário Terapêutico do INFARMED (11th ed., 2012) — Medroxyprogesterone, 16.2.1.3
Taking with high-fat food did not change medroxyprogesterone half-life in a clinically relevant way ("half-life of MPA was not changed with food") — it may be taken with or without food.
Take with or without food, according to gastric tolerance.
DailyMed/FDA (NIH/NLM) — approved Medroxyprogesterone label (PROVERA): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a586be28-96af-4fed-a13f-9b94fd4c7405
Contraindicated in active DVT/PE or a history of these conditions and in active arterial thromboembolic disease (PROVERA label).
Avoid in patients with active thrombosis or a history of thromboembolism; assess individual risk.
DailyMed/FDA (NIH/NLM) — approved Medroxyprogesterone label (PROVERA): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a586be28-96af-4fed-a13f-9b94fd4c7405
Suspected pregnancy is a contraindication (Prontuário); the hormone may affect fetal development.
Exclude pregnancy before starting and use effective contraception during treatment.
Prontuário Terapêutico do INFARMED (11th ed., 2012) — Medroxyprogesterone, 16.2.1.3
Suspected pregnancy is a contraindication; the hormone may affect fetal development — use only if the benefit justifies it.
Avoid in the first trimester; use only if clinically necessary under medical guidance.
The hormone passes into breast milk ("The hormone in PROVERA can pass into your breast milk") — caution during breastfeeding.
Exclude pregnancy before starting and use effective contraception during treatment.
DailyMed/FDA (NIH/NLM) — approved Medroxyprogesterone label (PROVERA): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a586be28-96af-4fed-a13f-9b94fd4c7405
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Progestogen with an antioestrogenic effect (suppression of gonadotrophin secretion and inhibition of growth of hormone-dependent tissues and tumours).
Exerts an antioestrogenic effect by suppressing pituitary gonadotrophin secretion (decreased oestradiol) and a direct cytostatic effect on hormone-dependent tumour cells; at low doses, endometrial and contraceptive effects.
Absolute oral bioavailability has not been formally investigated ("No specific investigation on the absolute bioavailability of MPA in humans has been conducted"); oral absorption is adequate.
Metabolised in the liver by hydroxylation, with conjugation and urinary elimination ("metabolized in the liver via hydroxylation, with subsequent conjugation and elimination in the urine"); the main pathway is CYP3A4.
Active metabolite with a half-life of a few hours; elimination is mainly renal after hepatic metabolism (conjugates).
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
